Homoleptic cerium tris(dialkylamido)imidophosphorane guanidinate complexes

Abstract

We report the synthesis of a new potassium tris(piperdino)imidophosphorane N,N′-dicyclohexylguanidinate, K[^CyGNP(pip)₃], and describe the synthesis and characterization of the tris-homoleptic compounds, [Ce(^CyGNP(pip)₃)₃], 1-Ce, and [Ce(^CyGNP(pip)₃)₃][BPh₄], 2-Ce. The latter is an unusual cationic tetravalent cerium complex. Cyclic voltammetry studies of 1-Ce and 2-Ce revealed E_pc potentials of −1.56 V and −1.81 V, and E_pa potentials of −0.78 V and −0.66 V (200 mV s⁻¹; THF, vs. Fc^0/+), respectively. Compounds 1-Ce and 2-Ce were studied by L₃-edge X-ray absorption near-edge spectroscopy (XANES), and the fit of the spectrum of 2-Ce revealed a white-line multiplet with an n_f value of 0.50(2).